Gluing unit for applying adhesive to a succession of opening devices for gluing to sealed packages of food products pourable into a tube of packaging material

ABSTRACT

A gluing unit for applying adhesive to a succession of opening devices to be fitted to respective sealed packages of food products pourable into a tube of packaging material, the unit having a conveyor for feeding the opening devices along a path, and an adhesive dispenser located along the path, interacting with each opening device to apply adhesive to a portion of the opening device, and movable in a plane parallel to the path as well as crosswise to the plane.

TECHNICAL FIELD

The present invention relates to a gluing unit for applying adhesive toa succession of opening devices for gluing to sealed packages of foodproducts pourable into a tube of packaging material.

BACKGROUND ART

As is known, many food products, such as fruit juice, pasteurized or UHT(ultra-high-temperature treated) milk, wine, tomato sauce, etc., aresold in packages made of sterilized packaging material.

A typical example of this type of package is the parallelepiped-shapedpackage for liquid or pourable food products known as Tetra Brik Aseptic(registered trademark), which is made by folding and sealing laminatedstrip packaging material.

The packaging material has a multilayer structure substantiallycomprising a base layer for stiffness and strength, which may comprise alayer of fibrous material, e.g. paper, or of mineral-filledpolypropylene material; and a number of layers of heat-seal plasticmaterial, e.g. polyethylene film, covering both sides of the base layer.

In the case of aseptic packages for long-storage products, such as UHTmilk, the packaging material also comprises a layer of gas- andlight-barrier material, e.g. aluminium foil or ethyl vinyl alcohol(EVOH), which is superimposed on a layer of heat-seal plastic material,and is in turn covered with another layer of heat-seal plastic materialforming the inner face of the package eventually contacting the foodproduct.

As is known, packages of this sort are produced on fully automaticpackaging machines, on which a continuous tube is formed from theweb-fed packaging material; the web of packaging material is sterilizedon the packaging machine, e.g. by applying a chemical sterilizing agent,such as a hydrogen peroxide solution, which, once sterilization iscompleted, is removed from the surfaces of the packaging material, e.g.evaporated by heating; and the web of packaging material so sterilizedis maintained in a closed, sterile environment, and is folded and sealedlongitudinally to form a vertical tube.

The tube is filled with the sterilized or sterile-processed foodproduct, and is sealed and subsequently cut along equally spaced crosssections to form pillow packs, which are then folded mechanically toform respective finished, e.g. substantially parallelepiped-shaped,packages.

Alternatively, the packaging material may be cut into blanks, which areformed into packages on forming spindles, and the packages are filledwith the food product and sealed. One example of this type of package isthe so-called “gable-top” package known by the trade name Tetra Rex(registered trademark).

Once formed, the above packages may undergo further processing, such asapplying a reclosable opening device to protect the food product insidethe package from contact with external agents, and to enable the productto be poured out.

At present, the most commonly marketed opening devices comprise anannular frame defining a pour opening and fitted about a removable orpierceable portion of a top wall of the package; and a cap hinged orscrewed to the frame, and which is removable to open the package.

The removable portion of the package may be defined by a sealing sheetglued or heat-sealed to the outside of the package to close a throughhole in the package. One example of this solution is described andillustrated in Patent Application EP-A-943549. Alternatively, theremovable portion of the package may be defined by a so-called“prelaminated” hole, i.e. a hole formed in the base layer of thepackaging material before covering the base layer with other layersdefining the packaging material, e.g. the layers of thermoplasticmaterial and/or the layer of barrier material, which close the holehermetically.

In both cases, before being applied to the respective packages, theopening devices are fed successively through a gluing unit, in whichthey are coated with adhesive, usually hot-melt glue.

As described for example in Patent Application EP-A-1798149, on whichthe preamble of claim 1 is based, gluing units are known substantiallycomprising a conveyor for feeding the opening devices along a givenpath, and an adhesive dispenser, which interacts with each openingdevice to apply adhesive to a flat fastening portion of the openingdevice frame.

More specifically, the adhesive is applied by moving the dispenser alonga flat application path parallel to the fastening portion plane.

Though reliable and efficient, the gluing units described still leaveroom for further improvement.

More specifically, a need is felt to apply the adhesive to the fasteningportion along predetermined trajectories and in predetermined amounts asrepeatably and controllably as possible.

This is particularly so in the case of opening devices comprising aframe straddling an edge between a first and second wall, e.g. the topwall and a top end portion of a lateral wall, of the package, andcomprising a first and second portion at an angle to each other andglued to the first and second wall respectively by respective fasteningportions inclined with respect to each other.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a gluing unit forapplying adhesive to opening devices for gluing to sealed packages ofproducts pourable into a tube of packaging material, and designed toachieve the above aim.

According to the present invention, there is provided a gluing unit forapplying adhesive to a succession of opening devices to be fitted torespective sealed packages of food products pourable into a tube ofpackaging material, as claimed in Claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred, non-limiting embodiment of the present invention will bedescribed by way of example with reference to the accompanying drawings,in which:

FIG. 1 shows a top view in perspective of a gluing unit, in accordancewith the present invention, for applying adhesive to a succession ofopening devices for gluing to sealed packages of food products pourableinto a tube of packaging material;

FIG. 2 shows a top view in perspective, with parts removed for clarity,of the FIG. 1 gluing unit;

FIGS. 3 and 4 show underside views in perspective of the FIG. 1 gluingunit from different angles;

FIGS. 5 and 6 show larger-scale views in perspective of details of theFIG. 1-4 gluing unit from different angles;

FIG. 7 shows a much larger-scale view in perspective of details of theFIG. 1-4 gluing unit;

FIG. 8 shows a particular opening device to which adhesive can beapplied by the FIG. 1-7 unit; and

FIG. 9 shows the FIG. 8 opening device applied to a package at a stationdownstream from the FIG. 1-7 unit.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to FIGS. 1 to 4, number 1 indicates as a whole a gluingunit, in accordance with the present invention, which can beincorporated in a known food product packaging machine (not shown) ofthe type described in the introduction, to apply adhesive—in the exampleshown, hot-melt glue—to a succession of reclosable plastic openingdevices 3 for gluing to packages filled, sealed, and formed on themachine.

Very briefly, a continuous tube is formed on the packaging machine fromthe web-fed packaging material. More specifically, the web of packagingmaterial is first sterilized on the packaging machine with a sterilizingagent that is subsequently removed; and the web of packaging material sosterilized is maintained in a closed, sterile environment, and is foldedand sealed longitudinally to form a vertical tube of packaging material.

The tube of packaging material is filled with the sterilized orsterile-processed food product, and is sealed and subsequently cut alongequally spaced cross sections to form pillow packs, which are thenfolded mechanically to form respective finished packages.

The machine preferably produces sealed packages of a pourable foodproduct, such as pasteurized or UHT milk, fruit juice, wine, etc.

The packaging machine may also produce sealed packages of a food productwhich is pourable into the tube of packaging material when producing thepackages, and sets after the packages are sealed. One example of such afood product is a portion of cheese, which is melted when producing thepackages, and sets after the packages are sealed.

Non-limiting examples of packages produced on packaging machines of thetype referred to above are the parallelepiped-shaped packages known bythe trade name Tetra Brik Aseptic (registered trademark) or so-called“gable-top” packages known by the trade name Tetra Rex (registeredtrademark).

The packaging material has a multilayer structure substantiallycomprising a base layer for stiffness and strength, which may comprise alayer of fibrous material, e.g. paper, or of mineral-filledpolypropylene material; and a number of layers of heat-seal plasticmaterial, e.g. polyethylene film, covering both sides of the base layer.

In the case of aseptic packages for long-storage products, such as UHTmilk, the packaging material also comprises a layer of gas- andlight-barrier material, e.g. aluminium foil or ethyl vinyl alcohol(EVOH), which is superimposed on a layer of heat-seal plastic material,and is in turn covered with another layer of heat-seal plastic materialforming the inner face of the package eventually contacting the foodproduct.

Opening device 3 is applied to a removable portion of a respectivepackage (shown by the dash line in FIG. 9), i.e. a portion detachablefrom the rest of the package to pour out the pourable product.

The removable portion may be defined by a sealing sheet glued orheat-sealed to the package to close a through hole in the package.Alternatively, the removable portion may be defined by a so-called“prelaminated” hole, i.e. a hole formed in the base layer of thepackaging material and closed hermetically by other layers (at least thelayers of thermoplastic material) of the packaging material.

FIGS. 1, 8 and 9 show one example of an opening device 3, to whichreference is made in the following description purely by way of anon-limiting example.

Opening device 3 substantially comprises:

-   -   a frame 5 which is applied about the removable portion of the        package, and has a circular opening 6 through which the food        product is poured;    -   a removable screw cap 7 fitted to frame 5 to close opening 6;        and    -   a cutting member 15 (FIG. 8) which, in use, engages opening 6        and interacts with the removable portion of the package to        partly detach the removable portion from the rest of the        packaging material and so open the package.

Frame 5 straddles an edge between two adjacent walls of the package,e.g. a top wall and a top end portion of a lateral wall adjacent to thetop wall (FIG. 9), and comprises two fastening portions 12, 13 at apredetermined angle to each other and fixed to the top wall and lateralwall of the package respectively.

More specifically, frame 5 comprises a flange 14 defining portions 12,13; and a threaded collar 16 (FIG. 8) defining opening 6 and forreceiving cap 7.

Portion 12 is substantially annular, and portion 13 projects fromportion 12 on the opposite side to collar 16.

The angle between portions 12, 13 of flange 14, on the opposite side, inuse, to the top wall and lateral wall of the package, is preferably 90°or over and less than 180°.

Collar 16 projects from flange 14 and, once opening device 3 is appliedto the package, extends from the opposite side of flange 14 to the sidefacing the top wall and lateral wall of the package.

With reference to FIGS. 1 to 4, unit 1 substantially comprises:

-   -   a conveyor (not shown) for feeding devices 3 along a straight        path A from a known feed station (not shown) to a known output        station (not shown);    -   a bed 20; and    -   an adhesive dispenser assembly 21 projecting outwards of bed 20        and comprising a number of—in the example shown, two—dispensers        22 which interact successively with each opening device 3 along        path A to apply adhesive to portions 12, 13 of frame 5.

More specifically, dispenser assembly 21 comprises a supporting body 23,from which dispensers 22 project; two rocker arms 24 fixed to supportingbody 23, on the opposite side to dispensers 22, and supported by bed 20;and a plate 19 interposed between and connected to rocker arms 24.

Dispensers 22 are movable in a direction Y parallel to path A, and in adirection X perpendicular to direction Y and defining with direction Y ahorizontal plane parallel to path A.

Opening devices 3 are conveyed on the conveyor with respective portions12 lying in plane P.

Dispensers 22 preferably slope with respect to plane P.

To move dispensers 22 in directions X, Y, unit 1 also comprises:

-   -   a motor 25 connected functionally to plate 19 of dispenser        assembly 21 by a transmission 26 to move dispensers 22 in        direction X with respect to bed 20; and    -   a motor 30 connected functionally to plate 19 of dispenser        assembly 21 by a transmission 31 to move dispensers 22 in        direction Y with respect to bed 20.

Rocker arms 24 extend substantially in direction X, and are positionedfacing a given distance apart in direction Y.

For each dispenser 22, dispenser assembly 21 comprises two adhesive feedlines 28.

Transmission 26 substantially comprises:

-   -   an endless belt 35 looped about a pulley 36 driven by motor 25,        and about a return pulley 37;    -   a slide 39 which is connected by an L-shaped member 42 to a        branch 38 of belt 35 parallel to direction X, and runs in        direction X inside a fixed runner 41 elongated in direction X;    -   a member 44 elongated in direction Y and having an outer profile        connected to an end portion 43 of slide 39 so as to be moved in        direction X by slide 39; and    -   a member 45 secured to an underside surface of plate 19 and        engaged by member 44 on the opposite side to plate 19.

More specifically, member 42 has two walls 46 fixed to opposite sides ofbranch 38 of belt 35; and a wall 47 fixed to the bottom of slide 39 andto walls 46.

Member 45 defines a cavity engaged by member 44, which has an outerprofile complementary to the cavity of member 44.

Members 45, 44 are so connected that movement of member 44 parallel todirection X also moves member 45 and dispenser assembly 21 parallel todirection X, whereas member 44 is free to slide parallel to direction Yinside the cavity defined by member 45.

In the example shown, the cavity defined by member 45 and the outerprofile of member 44 are dovetailed.

Similarly, slide 39 has an outer profile engaging and complementary to aseat defined by runner 41.

In the example shown, the outer profile of slide 39 and the seat definedby runner 41 are both dovetailed.

Unit 1 also comprises a counterweight 49 connected to the oppositebranch of belt 35 to branch 38, and which balances the moving masses andreduces operating vibration of transmission 26.

Transmission 31 comprises (FIGS. 3, 4 and 7):

-   -   an endless belt 50 looped about a pulley 55 driven by motor 30,        and about a return pulley (not shown);    -   a slide 51 which is connected to a branch 52, parallel to        direction Y, of belt 50 by two members 53 located on opposite        sides of branch 52, and is quadrangular in shape with two sides        parallel to direction X and two sides parallel to direction Y;    -   two members 56 elongated parallel to direction X and fitted to        an underside surface of slide 51, on the opposite side to belt        50, so as to be moved parallel to direction Y by slide 51; and    -   two members 57 (not visible in FIG. 7) fixed to a topside        surface of plate 19, on the opposite side to member 45, and        which are elongated parallel to direction X, and engaged by        respective members 56.

More specifically, on the opposite side to members 56, slide 51comprises two parallel members 58 elongated parallel to direction Y, andwhich run parallel to direction Y on two fixed runners 59 also elongatedparallel to direction Y.

Members 58 define respective dovetail cavities elongated parallel todirection Y and engaged by bottom portions of respective dovetail outerprofiles defined by runners 59.

Members 56 and 57 are so connected that movement of members 56 parallelto direction Y also moves respective members 57 and dispenser assembly21 parallel to direction Y, whereas members 57 are free to slideparallel to direction X inside respective members 56.

More specifically, members 56 define respective cavities elongatedparallel to direction X and engaged by the outer profiles of respectivemembers 57.

The outer profiles of members 57 are complementary in shape to thecavities defined by respective members 56.

In the example shown, the cavities of members 56 and the outer profilesof members 57 are dovetailed.

Transmission 31 also comprises a counterweight 34 connected to theopposite branch of belt 50 to branch 52, and which balances the movingmasses and reduces operating vibration of transmission 31.

Dispensers 22 are advantageously movable crosswise to plane P.

Dispensers 22 thus travel along an application path comprising a firstportion lying in plane P to apply adhesive to portion 12 of flange 14;and a second portion crosswise to plane P to apply adhesive to portion13 of flange 14.

More specifically, rocker arms 24 of dispenser assembly 21 are hinged toplate 19 about an axis B parallel to and at a distance from path A, toallow dispensers 22 to tilt with respect to plane P.

To move dispenser assembly 21 crosswise to plane P, unit 1 comprises amotor 60 having an output member (not shown) rotating about an axis Cparallel to direction Y; a pin 61 elongated along an axis D parallel toaxis B, and to which rocker arms 24 are hinged about axis D; and atransmission 62 interposed between motor 60 and pin 61 to convertrotation of the output member of motor 60 about axis C to rotation ofrocker arms 24 and therefore of supporting body 23 and dispensers 22about axis B.

More specifically, motor 60 operates independently of motors 25, 30.

Axes B, C, D are parallel, spaced apart, perpendicular to direction X,and parallel to and spaced apart from path A and direction Y.

More specifically, axis D is interposed between axes B and C.

Transmission 62 substantially comprises:

-   -   a cam 63 rotated by the output shaft of the motor along axis C;    -   a member 64 defining, integrally, a portion 65 having a        cylindrical seat, of axis D, engaged by pin 61; and an arm 66        projecting from portion 65 away from dispenser assembly 21 and        parallel to direction X; and    -   a cam follower 67 connected functionally to arm 66 of member 64        and to cam 63 to convert rotation of cam 63 about axis C to        translation of member 64 and pin 61 along an axis E        perpendicular to plane P, so as to rotate rocker arms 24 about        axis D.

More specifically, pin 61 and portion 65 of member 64 are integral witheach other as regards translation along axis E, whereas pin 61 is freeto slide parallel to axis D inside the seat defined by portion 65.

In the example shown, pin 61 and the seat defined by portion 65 haverespective mating splined profiles parallel to axis D.

Cam follower 67 (FIGS. 5, 6) substantially comprises a member 68elongated along axis E; and two rollers 69 defined by respective axialends of member 68 and cooperating with cam 63.

The interaction between cam 63 and rollers 69 also moves cam follower 67parallel to axis E.

Transmission 62 also comprises:

-   -   a lever 70 defined by a plate 75 fixed to member 68, and by an        arm 77 which projects from plate 75 towards dispenser assembly        21 and parallel to direction X, and is fixed to a surface of        member 68 on the opposite side to cam 63;    -   a slide 73 elongated substantially in direction X, and fixed to        an underside surface of arm 77 facing arm 66 of member 64; and    -   a runner 71 engaged by slide 73 and fixed to a topside surface        of arm 66 facing lever 70.

More specifically, slide 73 engages runner 71 to slide parallel todirection X; whereas movement of slide parallel to axis E moves runner71 and therefore member 64 and pin 61 parallel to axis E.

In the example shown, runner 71 defines a dovetail cavity elongatedparallel to direction X and engaged by slide 73; and slide 73 has adovetail outer profile complementary in shape to the cavity of runner71.

Transmission 62 comprises a plate 80 fitted through with the outputmember of motor 60 and supporting, on the opposite side to motor 60, twoL-section projections 81 located on opposite sides of member 68.

Projections 81 comprise respective runners 82 elongated parallel to axisE and fitted with respective slides 83 fitted to a surface of plate 75opposite motor 60.

More specifically, slides 83 slide along runners 82 parallel to axis E.

In the example shown, slides 83 define respective dovetail cavitiesparallel to axis E and engaged by respective runners 82, which in turnhave dovetail outer profiles complementary in shape to the cavities ofrespective slides 83.

In actual use, opening devices 3 are fed along path A with portion 12substantially coplanar with plane P, and portion 13 extending fromportion 12 towards dispenser assembly 21.

When opening devices 3 are positioned beneath dispenser assembly 21,each dispenser 22 is moved, from a start position, parallel to path A atthe same speed as a respective opening device 3.

As it moves parallel to path A, each dispenser 22 performs a work cyclecomprising a step in which adhesive is dispensed onto portions 12 and 13of respective opening device 3, and a step in which no adhesive isdispensed.

More specifically, during the step in which adhesive is dispensed, andas it moves parallel to path A, each dispenser 22 is moved, with respectto respective opening device 3, along the application path.

Each dispenser 22 applies adhesive to portion 12 of respective openingdevice 3 as it travels along the first portion of the application pathin plane P, and applies adhesive to portion 13 of respective openingdevice 3 as it travels along the second portion of the application pathoutside plane P.

More specifically, motor 25 and transmission 26 move dispenser assembly21 in direction X, motor 30 and transmission 31 move dispenser assembly21 in direction Y, and motor 60 and transmission 62 tilt dispenserassembly 21 with respect to axis B and plane P to allow dispensers 22 totravel along the second portion of the application path.

More specifically, motor 25 rotates pulley 36 to move branch 38 of belt35 parallel to direction X.

The movement of branch 38 of belt 35 parallel to direction X movesmember 42, slide 39, members 44, 45 and plate 19 parallel to directionX.

The above movement of plate 19 moves dispensers 22 parallel to directionX.

Vibration induced by operation of motor 25 and transmission 31 isbalanced by counterweight 49.

Motor 30 rotates pulley 55 to move branch 52 of belt 50 parallel todirection Y.

The movement of branch 52 of belt 50 parallel to direction Y moves slide51 by means of members 53.

Members 56 integral with slide 51, and members 57 fixed to plate 19 aredrawn along parallel to direction Y by slide 51.

The movement of plate 19 moves dispensers 22 parallel to direction Y.

Vibration induced by operation of motor 30 and transmission 31 isbalanced by counterweight 34.

Motor 60 rotates cam 63 about axis C; and cam 63 cooperates with rollers69 to move member 68, lever 70, and slide 73 along axis E.

The movement of slide 73 along axis E moves runners 71, member 64, andpin 61.

The movement of pin 61 tilts rocker arms 24, plate 19, and dispensers 22about axis B.

For example, when rollers 69 are raised with respect to axis C, rockerarms 24 and dispensers 22 rotate anticlockwise with respect to axis B inFIG. 4.

Conversely, when rollers 69 are lowered with respect to axis C, rockerarms 24 and dispensers 22 rotate clockwise with respect to axis in FIG.4.

Rotation of dispenser assembly 21 about axis B allows dispensers 22 totravel along the second portion of the application path to applyadhesive to portion 13 of flange 14 of respective opening devices 3.

As dispenser assembly 21 moves parallel to direction Y, pin 61 slidesparallel to axis D with respect to portion 65 of member 64.

The advantages of unit 1 according to the present invention will beclear from the foregoing description.

In particular, unit 1 provides for moving dispensers 22 crosswise toplane P defined by directions X and Y.

As a result, the trajectories of dispensers 22 and the amount ofadhesive applied to opening device 3 are controllable and repeatablemuch more accurately as compared with the known solutions described inthe introduction.

Moreover, dispensers 22 being movable crosswise to plane P, unit 1provides for applying adhesive quickly and controllably to both portions12 and 13 of opening devices 3, by simply feeding opening devices 3along path A, with no additional movements required.

Being tilted with respect to plane P, dispensers 22 can travel along theapplication path while remaining at substantially the same distance fromportions 12, 13 of the opening devices to which adhesive is applied.

The Applicant has observed that this provides for an extremely eventhickness of the adhesive applied to portions 12, 13, and greatlyreduces the risk of breaks in the layer of adhesive applied to portions12, 13.

Motor 60 being operated independently of motors 25 and 30, theapplication path is easily adjustable, thus greatly improving theversatility of unit 1.

Clearly, changes may be made to unit 1 without, however, departing fromthe scope as defined in the accompanying Claims.

In particular, dispensing assembly 21 may comprise only one dispenser22.

The invention claimed is:
 1. A gluing unit for applying adhesive to asuccession of opening devices to be fitted to respective sealed packagesof food products pourable into a tube of packaging material, the unitcomprising: conveying means for feeding said opening devices along apath; adhesive dispensing means which are located along said path,interact with each said opening device to apply said adhesive to aportion of the opening device, and are movable in a plane parallel tosaid path; and a bed supporting said adhesive dispensing means; saidadhesive dispensing means being hinged to said bed about a first axisparallel to said plane via at least one rocker arm so as to be tiltablewith respect to said plane and movable crosswise thereto; a drive memberand motion transmission means interposed functionally between said drivemember and said at least one rocker arm, and which, in use, rotate saidat least one rocker arm and said adhesive dispensing means about saidfirst axis; said motion transmission means comprising a cam connectedfunctionally to said drive member and rotating about a second axis, anda cam follower which cooperates with said cam, is moved by said camalong a third axis crosswise to said first and second axis, and isconnected functionally to said at least one rocker arm in a positiondistinct from said first axis.
 2. A gluing unit as claimed in claim 1,wherein said motion transmission means also comprise: a pin extendingalong a fourth axis parallel and distinct to said first axis, andmovable angularly with respect to said at least one rocker arm aboutsaid fourth axis; and a lever integral with said pin and said camfollower with respect to said third axis.
 3. A gluing unit as claimed inclaim 2, wherein said motion transmission means comprise a runnerintegral with said pin along said third axis, and a slide fixed to saidlever; said slide sliding, inside said runner, parallel to a directioncrosswise to said path, and being fixed with respect to said runneralong said third axis.
 4. A gluing unit as claimed in claim 3, whereinsaid transmission means comprise a member integral with said runner andconnected to said pin in sliding manner in a direction parallel to saidpath, and in fixed manner with respect to said third axis.
 5. A gluingunit as claimed in claim 4, wherein said pin and a portion of saidmember connected to the pin have respective splined profiles mating witheach other and elongated along said fourth axis.
 6. A gluing unit asclaimed in claim 1, wherein said adhesive dispensing means comprise atleast one dispenser tilted with respect to said plane.